Finite Element Simulation Of Edge Drop Control Characteristics Of Roll Shape Of Single-taper Work Roll Of UCMW Rolling Mill

This paper was based on the upgrade and optimization of the edge drop control system of a 1500 mm five-stand UCMW tandem cold rolling mill,the UCMW cold rolling mill was taken as the research object.Based on the elastic-plastic finite element method(FEM),the three-dimensional finite element model for coupling deformation analysis of roll and strip of UCMW rolling mill was established by using the finite element software ANSYS/LSDYNA.The edge drop control characteristics of roll shape of single-taper work roll of UCMW rolling mill were studied.The main contents are as follows:(1)The edge drop automatic control strategy of a six-high tandem cold rolling mill was studied.The trigger logic and execution process of the edge drop preset model,self-learning control model and closed-loop control mode in the edge drop automatic control system were elaborated specifically.The calculation methods of the key control parameters such as the preset value of the work roll shifting and the roll shifting adjustment amount were studied,and the important role of the control efficiency coefficient of work roll shifting,which is decided by end roll curve,was pointed out.(2)A high-precision three-dimensional finite element model of UCMW rolling mill that can be used for simulation experiments was established.The modeling process was described in detail,and the key problems,which influence the convergence and accuracy of the model calculation,such as the application of elastic roll rotation load,mesh division,and overall model mesh distribution were solved.Under the premise of ensuring the calculation accuracy,the finite element model was optimized from the three aspects of hourglass control,mass scaling and damping control to reduce calculation time.The deviation of the rolling force calculated value and the actual value is less than 7%,proved the validity of the finite element model.(3)The tapered section of the fixed single-taper work roll has a taper of 1/400 and a taper length of 155 mm.Six types of roll curves,including straight line,sinusoid,arc curve,cubic curve,quartic curve and fifth curve,were designed.The influence of work roll shifting on strip cross-section shape,flatness deviation,rolling pressure distribution and the contact pressure distribution between work roll and intermediate roll were analyzed under different end roll shapes by simulation.(4)A multi-objective function of work roll shifting which consider the influence of work roll shifting on edge drop,center crown,standard deviation of flatness distribution,unevenness of rolling pressure distribution and unevenness of contact pressure distribution between work roll and intermediate roll was proposed.The optimal range of work roll shifting and the suitable range of work roll shifting under different roll shapes were calculated with edge drop control as the primary goal.Considering the roll shifting capability of the mill and the adaptability to the rolling conditions,a sinusoid or a arc curve is considered as the better choice of roll shape.The research results of this paper can provide a reference for steel mills to design and choose the roll shape curve of the tapered segment of the single-taper work roll and determine the corresponding range of work roll shifting.